Table-operating mechanism for grinding-machines.



C. H. NORTON. TABLE OPERATING NIECHANISM FOR GRINDING MACHINES.

APPLICATION FILED, JULY 21, I9I4 l 15%21,

Patented Aug. 17, I915.

3 SHEETSSHEET I.

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APPLICATION FILED JULY 21, I914. w H

Pitented Aug. 17, I915.

' 3 SHEETS-SHEET 2.

Wnesses:

c. H. NORTON. TABLE OPERATING MECHANISM FOR GRINDING MACHINES.

APPLICATION FILED .IULY 2|, 1914.

3 SHEETS-SHEET 3.

Patented Aug. 17, 1915.

*N MN |1|IlI||.I.1|II| Ir n IIIII |1Il| IIII. IIII I IIILIII IIIIIII IIIIII ll IIIIFIIIIIIIIM Llmgi p Wwmss es snaps 1 I CHARLES H. NORTON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO NORTON GRINDING COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF ranssaonusnrrs.

TABLE-OPERATING MECHANISM FOR GRINDING-MACHINES.

; Specification of Letters Patent.

Patented Aug. 17; 1915.

Original application filed June 6, 1913, Serial No; 772,054. Divided and this application filed July 21, 1914.

Serial No.

To (ZZZ whom it may concern: Y

Be it known that I, CHARLES H. NoRToN, a citizen of the United States, residlng at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Table-Operating Mechanism for Grinding-Machines, of which the following. is a specification.

This invention relates to a table operating mechanism for a grinding machine and contains matter divided out of applicants prior application, Serial N 0. 772,054, filed J mac 6, 1913.

The principal object of my present invention is to provide improved means for receiving and relieving the end thrust upon the table driving worm caused by the reversal of the worm while the table is moving at high speed.

In'my improved construction the worm and the shaft upon which it is mounted is movable longitudinally for a. limited distance, and regulating devices are provided by which its rate of longitudinal movement may be controlled. By the use of this construction, the rate of travel for a table of given weight may be very materially increased without increasing the reversal strain upon the operating mechanism.

A preferred form of the invention is shown in the drawings in which,

Figure 1 is a front View of a machine having my improved device applied thereto; Fig. 2 is a. top plan view of the table-operating mechanism; Fig. 3 is a side view of the belt shifting mechanism; and Fig. 4 is an enlarged view of the controlling. devices.

The machine to which my invention is applied comprises a base 2 carried by adjustable supports 3 and having parallel Ways 4 upon its upper surface. The work-supporting table 5 is mounted to slide upon the ways 4 and has secured to its under surface a rack 6 meshing with a large gear or bull wheel 7. The

- 11 is provided with a key. fittifiigi-a iteywway formed in the sleeve. In the-drawing, the shaft 11 is shown as formed in two parts suitably connected. This construction is adapted for convenience of construction but for the purpose of this application the shaft may be regarded as a single element. The worm wheel 13 is thus non-rotatably connected' to the shaft 11, while the shaft is free to move longitudinally through the sleeve and worm wheel.

A worm 14 is mounted upon a horizontal shaft 15 (Figs. 2 and 4) and the worm wheel 13. The shaft 15 is supported in suitable bearings 16 :and 17 and is provided at its rear end with loose pulleys 18 and 19 and a narrow tight pulley 20. A power shaft 21 is arranged parallel to the shaft 15 and is suitably supported in bearings 22 on the frame of the machine. The shaft 21 may be driven by a belt 100' from any suitable source of power, and is provided with a wide-faced pulley 23 connected by straight and cross belts 24 and 25 with the pulleys 1'8, 19 and 20.

A belt shifting rod 26 (Fig. 2) is connected to reversing mechanism, not shown, and acts through a bell crank 27 and connecting rod 28 to move a sliding carriage 29. This carriage has grooved wheels 30 arranged in pairs thereon and running between stationhe carnage is also ary parallel rodsBl. provided with belt guides 32 for the belts 24 and 25. The reversing mechanism is controlled by adjustable stops upon the table and acts to reverse the rotation of the shaft 15 as the table reaches its limit of travel in either direction.

In Fig. 4 I have shown on an enlarged scale the regulating devices for relieving the end thrust on the worm shaft 11. .These devices comprise dash-pots having open cylinders'40 secured to the shaft 11 and each having an air passage 41 formed in the hub thereof. At its inner end the air communicates with the interior of the cylinder and at its outer end it is open to the atmosphere. A regulating screw 42. is mounted in the hub of adapted to close the air; passage 41 to any desired extent. A second air passage 43 is formed in the hub of the cylinder and cpmmunicates with a'v'aij-lve 44 so arranged that air maybe meshes with passage 41 i the cylinder and is' freely admitted through the valve into the interior of the cylinder but cannot pass through thepassage 43 in the opposite d1- reetion. g a, p r

Pistons keyed to the shaft 11, which is freely mot 'ab'le longitudinally therein.

These pistons; are PIOVldBd with packing rings of usual form and fit closely within the cylinders 40. At their opposite ends the pistons.are*- provided with plates 51 WlllCl'l are confined longitudinally between ball bearings 52 am plates 53 secured to the casing 13 whio supports the worm wheel 13 and the worm shaft 15. The pistons are thus rotatable with theshaft 11' and with the cylinders 40 but are held from longitudinal movement relative to the casing 13.

Having described the construction of the apparatus, I willnow explain its operation. With the parts in the position shown in Fig. 2, it may be assumed that the table is being driven toward the left in Fig. 1. When the direction of rotation of the shafts 15 and 11 is reversed, the momentum of the table 5 will tend to continue its movement toward the left while the worm 10 will be rotating in a direction to drive the worm wheel 9* and the gear 7 in the opposite direction. A strong end thrust will thus be exerted by the worm wheel 9 upon the worm 10.- When the shaft 11 is rigidly secured to the worm wheel 13, as is the common practice, the permissible rate of table travel is limited by this end thrust. With my improved connections, however, the shaft 11 is permitted to move longitudinally through the sleeve 12 and wheel 13, this movement being yieldingly resisted by the air within the right-hand cylinder 40. The rate at which the air escapes from this cylinder may a be regulated, as previously explained, by adjustment of the screw 42. As the shaft moves to the left, the valve 44 in the lefthand'cylinder will open to freely admit air in the rear of the left-hand piston. In this manner the worm l0 and shaft 11 is permitted to movewith the worm wheel 9 until the speed of the table has been materially reduced or until the table has actually stopped. The right-hand cylinder 40 eventually contacts with the right-hand piston 50 and the shaft 11 is thereafter driven as if rigidly connected to theworm wheel 13.

Having thus described my invention, it Will be evident that many changes and modifications can be made therein by any one skilled in the art without departing from the spirit-and scope of my invention as set Therefore, I do not wish to be limited to the details herein disclosed, but- What I do claim is:-

1. In a grinding machine, in combination,

a'work table, reversible means to move said table longitudinally in either direction, said but secured against movable shaft supporting said worm, a bear- .ing for said shaft, means to rotate said shaft,

and devices effective to yieldingly resist longitudinal movement of saidshaft.

2. In a grinding machine, in combination, a work table, reversible means to move said table longitudinally in either direction, said means including a worm wheel and a worm for driving said wheel, a longitudinallymovable shaft supporting said worm, a hearing' for said shaft, means to rotate shaft, devices effective to yieldingly resist longitudinal movement of said shaft, and means to regulate the yielding resistance of said devices.

3. In a grinding machine, in combination, a work table, reversible means to move said table longitudinally in either direction, said means including a worm wheel and a worm for driving said 'wheel, a longitudinallymovable shaft supporting said worm, a driven sleeve within which said shaft is longitudinally movable and by which it is .said wheel, a shaft slidably keyed in said wheel, a worm on said shaft, table operating means operable thereby, and means to resist longitudinal movementof said shaft in said worm wheel, said means comprising a. cylinder and-a piston, one of said parts being fixed to said shaft and longitudinally movable therewith, and the other part being rotatable with said shaft but fixed against longitudinal movement therewith.

In a grinding machine, in combination, a work table, reversible means to move said table longitudinally in either direction, said means including a worm wheel and a worm for driving said wheel, a longitudinallymovable shaft supporting said worm, a bearing for said shaft, means to rotate said shaft, and devices effective to yieldingly resist longitudinal movement of said shaft, said devices comprising a cylinder and a piston, one of said parts being fixed to said shaft and the other part being rotatable therewith longitudinal movement therewith.

6'. In a grinding machine, in combination,

said

a work table, driving means therefor ineluding a worm and a reversible longitudiinally-movable worm shaft, a bearing for said shaft, and means to yieldingly resist longitudinal movement of said shaft relative to said rearing, said means comprising a cylinder and apiston, one of said parts being fixed to said. shaft, and the other being rotatable therewith but held by said bearing from longitudinal movement with said shaft, said sage therefrom, opening to said passage.

7. In a grinding machine, in combination, a Work table, driving means therefor including a Worm and a reversible longitudinally-movable worm shaft, a bearing for said shaft, and means to yieldingly resist longitudinal movement of said shaft relative to said'bearing, said means comprising a cylinder and a piston, one of said parts being fixed to said shaft, and the other being rotatable therewith but held by said hearing from longitudinal movement with said shaft, said cylinder having an air inlet 7 connected thereto and having a valve in said inlet through which air may one direction only.

8. In a grinding machine, in combination, a work table, reversible means to move said table longitudinally in either direction, said means including a worm wheel and. a worm for driving said wheel, a "longitudinallymovable shaft supporting "said worm, a bearing for said shaft, means to rotate said shaft, and devices effective to yieldingly resist longitudinal movement of said shaft, said devices comprising a pair of dash-pots pass freely in with their cylinders fixed in opposed relation on said shaft and their pistons rotatable with said shaft but confined against longitudinal movement therewith.

9. In a grinding machine, in. combination, a work table, reversible means to move said table longitudinally in either direction, said means including a worm Wheel and a worm for driving said Wheel, a longitudinallymovable shaft supporting said worm, a bearing for said shaft, means to rotate said shaft, and devices effective to yieldingly resist longitudinal movement of said shaft, said devices comprising a pair-of dash-pots with their cylinders fixed in opposed relation on said shaft and a pair of pistons cylinder having an air pas-' and means to vary the air gaging the mounted to rotate with said shaft and slida ble thereon, said pistons having portions enbearing of said shaft and confined against longitudinal movement relative thereto.

10. In a' grinding machine in combina tion, a work table, driving means therefor including a. worm and a reversible longitudinally-movable worm shaft, a bearing for said shaft, and means to yieldingly resist longitudinal movement of said shaft relative to said bearing, said means comprising a pair of dash-pots, each having a cylinder fixed to said shaft and a piston rotatable therewith but slidahle thereon, and held from longitudinal movement by said bearing, said cylinders being opposed and having air inlets, and adjustable air outlets in their huh portions.

11. In a grinding machine, in combination, a work table, driving means therefor including a longitudinally movable shaft, means to rotate said shaft, and yielding means to resist longitudinal. movement of said shaft and to thereafter positively limit said movement. v

12. In a grinding machine, in combination, a wort table, driving means therefor including longitudinally movable shaft, means 'to rotate said shaft, and yielding means to resist longitudinal movement of said shaft and to thereafter positively limit said movement, said means comprising a. member mounted on (linallv movable therewith, and a second member alined with said shaft but held. from longitudinal movement.

In testimony whereof I have hereunto set my hand, in the presence of two subscribing" Witnesses.

CHARLES H. NORTON. iVitnesses I OW RD W, DUNBAR 7 A. G. BELDEN.

said shaft and longitu- 

